Plate heat exchangers, PHEs, typically consist of two end plates in between which a number of heat transfer plates are arranged in an aligned manner, i.e. in a stack. To be properly positioned between the end plates, the heat transfer plates may engage with an upper carrying bar and a lower guiding bar, which bars extend between the end plates. In one type of well-known PHEs, the so called gasketed PHEs, gaskets are arranged between the heat transfer plates, typically in gasket grooves which extend along edges of the heat transfer plates. The end plates, and therefore the heat transfer plates, are pressed towards each other by means of some kind of tightening means, whereby the gaskets seal between the heat transfer plates. The gaskets define parallel flow channels between the heat transfer plates through which channels two fluids of initially different temperatures alternately can flow for transferring heat from one fluid to the other.
For a PHE to work properly, it may have to be cleaned at regular intervals, naturally depending on, among other things, the nature of the fluids fed through the PHE. In connection therewith, an operator typically loosens the tightening means before separating the end plates to open the PHE. In the open PHE the heat transfer plates are separable from each other by being pushed or pulled along the carrying and guiding bars. Typically, the operator washes one side of a first heat transfer plate before moving the first heat transfer plate to make the other side of it accessible. Thereafter, the operator washes the other side of the first heat transfer plate. This procedure is then repeated for each of the remaining heat transfer plates. The heat transfer plates are typically washed by being swilled off with water.
Cleaning of a PHE in the above described way may be time-consuming, especially if the PHE contains many and large heat transfer plates. Also, when cleaning large heat transfer plates, it may be difficult to reach upper portions of the heat transfer plates. The operator may have to use a ladder or similar which may be tiresome and associated with danger. Further, due to the human factor, some of the heat transfer plates may be carefully cleaned while others may be less carefully cleaned.